Service manual
35
9
Combined Refrigerant Piping Systematic Drawings
(Master unit back-up operation: Cooling mode)
Emergency Operation when Inverter Unit has Failed
Propeller fan
Check joint (Pd)
4-way valve
Check
valve
Check
valve
Check valve
Check
valve
Check
valve
Check
valve
Accumulator
Check
joint (Ps)
Capillary
Capillary
Capillary
Capillary
Fixed-speed
Inverter
Compressor
Capillary
Sensor
(TE1)
Sensor (TS)
Sensor
(TK1)
Sensor
(TK2)
Sensor
(TD1)
Sensor
(TD1)
Sensor
(TK3)
Sensor
(TD2)
Strainer
Strainer
Strainer
Strainer
Strainer
Strainer
Strainer
Strainer
Fan Motor
PMV (A)
PMV
PMV
PMV
Liquid
tank
Dryer
(x2)
Oil
separator
Condenser
Condenser
Pulse motor valve B
(Cooling bypass)
(PMVB)
Solenoid valve
(SV2)
High-
pressure
sensor
Low-
pressure
sensor
High-
pressure
SW
High-
pressure
SW
Solenoid valve
(SV3C)
Solenoid
valve
(SV3B)
Solenoid
valve
(SV3A)
Compressor
case oil
removal valve
Solenoid
valve
(SV42)
M
Service
valve
(gas side)
Oil tank
Packed
valve (oil
balancing
pipe)
Packed
valve
(liquid
side)
MM-A0280HT
Master unit 1 (Inverter)
MM-A0280HX
Slave unit 2 (Fixed-speed)
MM-A0280HX
Slave unit 3 (Fixed-speed)
MM-A0280HX
Slave unit 4 (Fixed-speed)
(Indoor unit 1)
(Indoor unit 2)
TC1
TC2
TC1
TC2
Pressure
sensor
Pressure
sensor
Check
joint
Check
joint
TA
(Ambient
sensor)
TA
(Ambient
sensor)
Strainer
(Indoor unit 3)
Evaporator
Evaporator
Evaporator
TC1
TC2
Pressure
sensor
Check
joint
TA
(Ambient
sensor)
(Solid line) High-pressure gas or compressed liquid refrigerant
Service valves closed fully at liquid and gas side.
(Dotted line) Evaporating gas refrigerant (Low-pressure gas)
Propeller fan
Check joint (Pd)
Check
valve
Check
valve
Check
valve
Check valve
Check
valve
Check
valve
Check
valve
Accumulator
Check
joint
(Ps)
Capillary
Capillary
Capillary
Capillary
Capillary
Fixed-speed
Fixed-speed
Compressor
Capillary
Sensor
(TE1)
Sensor (TS)
Sensor
(TK1)
Sensor
(TK2)
Sensor
(TK3)
Sensor
(TD2)
Strainer
Strainer
Strainer
Fan Motor
PMV (A)
Liquid
tank
Dryer
(x2)
Oil
separator
Pulse motor valve B
(Cooling bypass)
(PMVB)
Solenoid valve
(SV2)
High-
pressure
sensor
Low-
pressure
sensor
High-
pressure
SW
High-
pressure
SW
Solenoid valve
(SV3C)
Solenoid
valve
(SV3B)
Solenoid
valve
(SV3A)
Compressor
case oil
removal valve
Solenoid
valve
(SV41)
Solenoid
valve
(SV42)
Condenser
4-Way valve
Condenser
M
Service
valve
(gas side)
Oil tank
Packed
valve (oil
balancing
pipe)
Packed
valve
(liquid
side)
HP
HP
HP
HP
Service
valve
(gas side)
Packed
valve (oil
balancing
pipe)
Packed
valve
(liquid
side)
Service
valve
(gas side)
Packed
valve (oil
balancing
pipe)
Packed
valve
(liquid
side)
Failure
Temporal setup
master unit
in emergency